Use of Solar Power in Multi-story Buildings

There are ways to do it, maybe not take it completely off the grid, but was to mitigate costs. A lot of the cost savings has more to do with tax breaks and other incentives rather than paying less for power though (at least in the short term).Here is a link to a factory that is solar powered

At locations where there is power shortage from grid, it will be necessary to justify capital investment,for installation of solar power systems (from returns on investment considerations),to receive financial approvals. Financial impact is high in bulk installations. Given a choice to either avail power from grid or from solar energy,which will be cheaper option,from the economic considerations,on life cycle cost - capital cost,operating and maintenance costs,put together? Kindly advise.

If there is a power shortage then having an independent power supply is vital. Wither that is solar, turbine generators, hydroelectric or even diesel power. With rising fuel prices I would say that a good solar array is cheaper in the long run.
Here is a link to a resource to help you do cost vs. benefits.
I hope others might be able to help you out as I only know a little about residential applications for solar energy and only in the US.

Rensselaer Polytechnic Institute's Lighting Research Center publishes good information on energy-efficient lighting for residential and commercial applications. You can find these publications here... https://www.lrc.rpi.edu/

At locations where there is power shortage from grid, it will be necessary to justify capital investment,for installation of solar power systems (from returns on investment considerations),to receive financial approvals. Financial impact is high in bulk installations. Given a choice to either avail power from grid or from solar energy,which will be cheaper option,from the economic considerations,on life cycle cost - capital cost,operating and maintenance costs,put together? Kindly advise.

Your question has far too many variables particular to your circumstances for anyone here to advise you effectively. I would suggest you "pick the brains" (standard designer methodology) of locally applicable suppliers of these systems and have them present their projection data as relevant to your application. So much easier, as it is what their technical sales people are paid to do.